Flu (Influenza)

Every year, millions of people get the flu. The good news is that the seasonal flu vaccine can lower the risk of getting the flu by about half. Getting the yearly flu vaccine is the best way to protect yourself from the flu.

Most people who get the flu have a mild illness. But for some, it can be serious — and even deadly. Serious complications from the flu are more likely in babies and young children, pregnant women, older adults, and people with certain long-term health conditions — like diabetes or asthma.

Getting vaccinated every year is the best way to lower your chances of getting the flu. Flu vaccines can’t cause the flu. Keep in mind that getting the flu vaccine also protects the people around you. So when you and your family get vaccinated, you help keep yourselves and your community healthy.

It’s important to get the flu vaccine every year. That’s important for 2 reasons: first, immunity (protection) decreases with time. Additionally, the flu viruses are constantly changing — so the vaccine is often updated to give the best protection.

People at increased risk for complications from the flu

It’s especially important for people who are at high risk of developing complications from the flu to get the vaccine every year. People at high risk for complications from the flu include:

Pregnant women

Adults age 65 years and older

Children younger than 5 years — and especially children younger than 2 years

People with long-term health conditions like asthma, diabetes, or cancer

Aim to get your flu vaccine by the end of October

Try to get the flu vaccine by the end of October. It takes 2 weeks for your body to develop immunity. So it’s best to get the flu vaccine before the flu starts to spread in your community.

If you don’t get the vaccine by the end of October, that doesn’t mean you shouldn’t get it — getting vaccinated later can still help protect you from the flu. You can get vaccinated at any time throughout the flu season.

Health care professionals and caregivers

It’s also very important for people who spend a lot of time with people at high risk for complications from the flu to get the vaccine — for example, health care professionals and caregivers.

Side effects are usually mild and go away in a few days. These side effects aren’t the flu — the flu vaccine can’t cause the flu.

Side effects from the flu vaccine may include:

Pain, swelling, or redness where the shot was given

Headache

Muscle aches

Fever

Upset stomach

Serious side effects from the flu vaccine are very rare.

Like any medicine, there's a very small chance that the flu vaccine could cause a serious reaction. Keep in mind that getting the flu vaccine is much safer than getting the flu. Learn more about vaccine side effects.